The brown anole, a nonnative lizard and common sight in Florida, has long served as an important host for disease-carrying mosquitoes. However, its population in South Florida may be declining, apparently displaced by the more recent arrival and spread of the Peters’s rock agama, an aggressive and large nonnative lizard.

“This battle over Florida territory by two lizard species may seem minor, given the myriad of problems that Florida faces from other invaders such as Burmese pythons,” said Nathan Burkett-Cadena, associate professor at the UF/IFAS Florida Medical Entomology Laboratory (FMEL). “However, this reptile rumpus could have implications for public health.”

A team of University of Florida scientists is looking to unveil those implications in a one-year study, while focusing on how these reptiles are influencing the spread of diseases like West Nile virus, St. Louis encephalitis and Eastern equine encephalitis.

The study, “Invasive lizard-mediated risk of mosquito-borne pathogen transmission,” is one of seven projects funded by a $350,000 grant from UF’s Invasion Science Research Institute. The team is addressing critical ecological issues in the state caused by the spread of the Peters’s rock agama.

“It’s possible that brown anole lizards have been unwittingly and unintentionally protecting us from West Nile virus and some other mosquito-transmitted diseases,” said Burkett-Cadena, principal investigator of the study. “Any time a mosquito bites a lizard, it doesn’t bite a bird or a human. This could result in fewer cases of mosquito-borne disease, because birds are natural hosts of some dangerous mosquito-transmitted viruses.”

The Peters’s rock agama may be changing all that by reducing the numbers of brown anole lizards that are available for mosquitoes to bite, and mosquitoes don’t bite the rock agama because they sleep in crevices where the mosquitoes can’t or don’t go, said Burkett-Cadena.

Together with co-principal scientists Melissa Miller, a research assistant scientist in invasion ecology at the UF/IFAS Fort Lauderdale Research and Education Center, and Lawrence Reeves, an assistant professor of entomology at FMEL, they will look at how invasive lizards, like the Peters’s rock agama, affect which animals mosquitoes bite and how this influences the spread of diseases in Florida.

Here is a brief overview from the team on what they will be focusing on during the research.

Q: What is the most important outcome you hope to learn from the study?

A: (Burkett-Cadena) We hope to show that invasive species have a lot of indirect consequences that are difficult to imagine before they establish. This will hopefully highlight the importance of programs that manage invasive species.

Q: Why is Florida particularly vulnerable to nonnative reptiles, and how many of these species are established in the state?

A: (Miller) Florida is a hot spot of biological invasions, particularly for reptiles, primarily due to its warm climate, major ports of entry, a thriving reptile trade and destructive storms that can facilitate escapes. At least 54 species of nonnative reptiles are established and breeding in Florida.

Q: What role does Peters’s rock agama play in this ecosystem?

A: (Miller) Since its introduction, Peters’s rock agama has spread to at least 20 counties in Florida. Agamas impact our native wildlife directly through predation and competition. However, less conspicuous impacts, such as the potential for agamas to alter disease transmission, are less understood and warrant further investigation.

Q: Why is it important to study the indirect impacts of invasive species on mosquito-borne parasites and pathogens?

A: (Reeves) When nonnative or invasive species move, they have diverse impacts on the ecosystems they invade. Some of these are direct, like the Burmese pythons in southern Florida eating mammals and other vertebrates. Others are indirect effects, like Burmese pythons eating racoons that would normally eat turtle eggs, leading to more turtles hatching. These impacts extend to the transmission of mosquito-borne parasites and pathogens. Transmission of many of these are influenced by the diversity and abundance of the available animals.

As a result, the introduction of new animal species into a system can directly or indirectly change how and how much these pathogens are transmitted. Studying the indirect impacts of invasive species on mosquito-borne parasites and pathogens allows our understanding of transmission and risk to humans to be up to date, helping us better address issues in mosquito-borne disease.

Q: What are the main objectives of your research on Peters’s rock agama?

A: (Reeves) We are investigating how the presence or absence of these lizards affects the types of animals that are bitten by mosquitoes and how those impacts influence the transmission of avian malaria. It has a similar transmission cycle to West Nile virus, the most widespread mosquito-spread pathogen affecting people in Florida.

Q: What are the potential implications of your research for wildlife management and public health in Florida?

A: (Burkett-Cadena) Wildlife managers can prioritize their budgets and personnel to manage invaders that have consequences for human health.